My daughter was 9 weeks old (yes, 9 WEEKS) the first time I flew with her. If you are prepared, things can go well. However, keep in mind... you can't control everything. Somethings will just happen and all you can do is deal with the situation at that time.
But... to prepare yourself, as suggested, the best thing to do is to have him suck on something. Drinking from a sippy cup, sucking on a lolli, or if he still uses a pacifier will greatly help. Also, you can pull up and out on his ears. It helps to relieve pressure in their inner ear. This is what I did with my daughter (as suggested by my chiropractor) and she did absolutely FABULOUS! Seriously... not one peep.
To combat boredom ... interesting toys, as suggested maybe new ones from the dollar store. I would avoid any medications to induce sleeping. That just sets the stage for nasties down the road.
Be calm .... don't give off vibes of anxiety or fear... he will pick up on that. Be excited about the flight. Be prepared (snacks are good too to keep them occupied. Besides..plane food sucks!)
Good luck!